1. Field of Invention
The present invention relates a method and system for using the Global Positioning System and wireless communications technology to notify third parties of accidents.
2. Background of Invention
GPS is used to track vehicle positions. GPS includes a plurality of satellites orbiting the earth at a substantially constant speed and altitude. Each satellite transmits a code sequence that identifies the satellite and a GPS navigation message that is superimposed on the code sequence. Although the satellites are assigned frequencies at which they send their signals, Doppler effect prevents the signals from appearing exactly at the assigned frequencies. Thus, a GPS receiver often searches through a predefined range of frequencies to find the signal from the GPS satellites before tuning in to acquire the code sequence and the superimposed information. The superimposed information includes positional information (e.g., latitude, longitude, and altitude if necessary) and the time at which those positions were obtained. Further details on obtaining positional information from GPS satellites are provided in U.S. patent application Ser. No. 09/707326 to Fan et al. entitled xe2x80x9cSystem and Method for Distribution of GPS Satellite Information,xe2x80x9d and in U.S. Pat. No. 5,959,577 to Fan et al. entitled xe2x80x9cMethod and Structure for Distribution of Travel Information Using Network.xe2x80x9d Both of the cited references are herein incorporated by reference.
Currently, the use of GPS is limited to tracking vehicle positions. Although vehicle safety is a concern for many people, GPS is not used as a tool for enhancing vehicle safety. Most reliable vehicle safety features today, such as seatbelts, air bags, and impact resistant bumpers, reduce the harm occupants might suffer as a result of a collision. However, the vehicle safety features available today do not focus on providing prompt notification of accidents to third parties. Once a collision occurs, prompt notification of third parties is desirable for accurate recording of the details of the collision and for calling for necessary medical care. The vehicle occupants may not be able to notify third parties due to a severe injury, and bystanders might not call for help. Therefore, a system that automatically and promptly notifies third parties of accidents is needed.
The present invention provides a method and a system using the Global Positioning System (GPS) to detect and report vehicle accidents. A mobile unit that can be placed or installed in a vehicle receives code sequences from the GPS satellites and converts the code sequences to positional information. The mobile unit transmits the positional information to a server at regular time intervals using a data network. The server derives the acceleration of said mobile unit based on the positional information and compares the absolute value of the derived acceleration with a threshold value.
The threshold value represents the maximum rate of acceleration that can be achieved by normal driving actions, such as braking or speeding up. A derived acceleration value greater than the threshold value indicates that an external factor, such as a collision, is involved. Thus, upon detecting an acceleration value that exceeds the threshold value, the server automatically sends an accident notification to third parties through the data network. The notification may include, for example, the map of the area surrounding the accident site, air bag deployment status, seatbelt status, and the speed at which the vehicle was traveling at the time of the accident.